Closure devices for drink pouches and containers are known in various embodiments from various documents, and are known to be obtainable on the market. On the part of the applicant, U.S. Pat. No. 5,020,690 is seen as being one of the earliest documents describing such a closure device. This reference describes a closure device where the catch means in the screw cap serves to encourage a movement of the piercing means running in the axial direction. The piercing means does not rotate, but rather employs only an axial, translatory motion according to the action of the catch means. The rotation required for achieving a screw motion is prevented by cams on the piercing means that are arranged on suitable guides in the pour-out spout.
The cutting element with the mentioned embodiment according to the '690 patent is formed of a multitude of teeth. A solution which is known from U.S. Pat. No. 5,141,133 is comparable. Here, the cutting element consists of a continuous peripheral gapless series of teeth which border one another, so that the piercing means practically has the shape of an annular saw tooth. This solution otherwise has the same drive system as the previously described embodiment according to '690 patent.
In all previously mentioned references the piercing means as a result have a purely axial translatory movement without any rotation. This means that the piercing means is literally pushed through the packaging material of which the receptacle consists. For this, one needs to know that all closure devices which correspond to the initial mentioned construction type, up to this date, have been attached onto receptacles which are manufactured of a multi-layered material and essentially consists of paper and/or cardboard with additional extraordinarily thin layers of plastic and/or aluminum. The cutting elements which consists of a multitude of teeth as already mentioned, could only carry out a perforation with their tips. In order for corresponding closures to be capable of functioning at all, the receptacles needed to have a part-punching (part-perforation) or part embossing by way of which the packaging material was already greatly weakened. Such a pre-punching means that the cylindrical pour-out spout of the lower part's opening needed to be attached over this pre-punching in an as congruent as possible manner. This is extremely difficult with regard to technology, in particular since the attachment of the lower part's opening may not be placed in an exact manner with a mechanical connection, but rather the opening of the lower part needs to be bonded onto the packaging, and with the manufacturing speeds required today, a deviation is always present in practice. Accordingly, the dimensions were designed such that a certain tolerance is permitted. Thus, the pre-punching is dimensioned somewhat smaller that the free diameter of the cylindrical pour-out spout. The rejection rate with closures of this construction type were extremely high despite these precautionary measures. These rejects were not only caused by the fact that the hardly realizable accuracy could not be kept, but also because of the problem of a suitable adhesive dosing/metering in order to bond the lower part opening onto the film. Even slight excesses of adhesive lead to the adhesive also partly being squeezed towards the center when pressing-on, and thus this adhesive reaches precisely the region of the pre-punching. As soon as the adhesive is cured, one may no longer realize a correct and perfect severing of the packaging material by way of the piercing means. Logically, a problem also results when using too little adhesive, since then the bonding of the lower part's opening on the film-like packaging material is inadequate and when rotating on, the piercing means has practically only pushed off the foil of the packaging material from the flange of the pour-out spout.
After this problem was recognized, closure devices of the initially mentioned type have been realized, with which the piercing means was no longer advanced in a purely translatory movement, but as initially mentioned, the piercing means was then moved downwards while twisted in a helical manner. For this, suitable catch means were provided in the screw cap, which cooperate with correspondingly cooperating catch means in the piercing means. Solutions of this type are known for example from U.S. Pat. Nos. 5,297,696, 5,482,176 and 5,960,992. However all these devices continue to demand a pre-punching of the film material of which the receptacle consists, and furthermore with these solutions, the cutting means is always realized by a continuous crown of teeth. Thanks to the screw movement which was then effected, these teeth in practice executed a sawing activity. Added to this is the fact that a certain eccentric attachment of the closure device relative to the pre-punching was less pragmatic, since the teeth crown, given the eccentricity, crosses the pre-punching at least once, usually twice, and thus at least one tooth may penetrate there and thus perform the perforation of the plastic film layer. Since the plastic is embedded, this may no longer expand more than specifically in the narrow slot-like region of the pre-punching which is only a few hundredths of a millimeter. The teeth thus on the one hand could sever the paper/cardboard layers in the manner of a saw and thus perforate the plastic film as soon as the teeth engaged the plastic film. With this, the multitude of teeth was seen as an advantage, since a multitude of perforations arise due to this.
However it has been ascertained that a plurality of perforations per se results in no advantage. Rather, it has been shown that a multitude of teeth automatically leads to the fact that these teeth need to be relatively weak. Whilst this is of hardly any relevance with regard to the perforation as long as the teeth are sharp, it has however been shown that the severing of the essentially thicker main layers of paper and cardboard in a saw-like manner leads to the fact that these teeth become blunter on the one hand, and get surrounded by fibers on the other hand, and the result of this is a lower perforating ability.
Accordingly, further developments have proceeded from this recognition, with which on the one hand the number of teeth were reduced and on the other hand the shape of the teeth were designed differently. Thus for example a solution with a number of equally high teeth which are distributed over the periphery in a non-uniform manner is known from European Patent Application No. 1,415,926. Finally, according to U.S. Pat. No. 6,279,779, a closure device with a piercing means is disclosed which only has a single tooth. This tooth is designed in a suitably strong manner and has different surfaces with a different effect. Thus the tooth has a sharp-edged, angular region which serves for perforation, as well as a cutting region. Thanks to its suitable thickness, it simultaneously also has a repelling function, where this repelling function is realized by a separate displacer that is likewise arranged on the piercing means. The one-tooth version has definitely not proven its worth. The procedures of severing the cardboard, the perforation of the plastic film component and cutting the complete material and finally folding away the cut-out part have not been able to be optimized with a single element.
The documents which have been described in detail earlier, which show closure devices with a cylindrical piercing means with which the complete lower piercing means edge is provided with a multitude of equally high teeth led to the fact that practically all teeth simultaneously reached the film to be pierced. With this however, the force necessary for severing the plastic films was increased enormously. The elasticity of the film for this reason did not lead to the desired effect, that with the impinging of the teeth, the perforation is severed practically equally to the contact of a soap bubble. In order to avoid this negative effect, Japanese Patent Application No 11-171233 suggests a solution with a plurality of teeth which are all arranged at different heights. The force for severing the film is reduced by way of this.
As already mentioned initially, all previously known closure devices of the initially mentioned type which may be obtained on the market, with regard to their design have been conceived for a packaging material which as mentioned, consists of mixtures of the most different of materials, and in particular contains a high constituent of paper and cardboard. Such packaging material has a corresponding strength which is desired in certain cases, but with regard to those cases in which in particular the waste volume is to be reduced, as well as other properties which are not being discussed in detail here, are to be achieved, packaging material that consists essentially of only one plastic film and merely has one or more additional blocking layers of other materials is suitable, wherein these blocking layers have a thickness in the region of several μ. All previously known closure devices are completely unsuitable for such materials.